The invention relates to a plug-in connector comprising a plug member to be secured on a counterpart by a locking device. The locking device has at least one locking element that, in an release position, enables detaching the plug member and the counterpart from one another and, in a locking position, locks the plug member and the counterpart relative to one another.
A plug-in connector with a locking device between the plug member and the counterpart is disclosed, for example, in DE 101 21 675 A1. The locking device of this plug-in connector is realized by a snap-on connection between plug member and counterpart. A lock sleeve is provided for the locking action. The lock sleeve is supported so as to be longitudinally slidable on the outer circumference of the snap-on element; in its locking position, the lock sleeve prevents outward pivoting of a snap hook and, in this way, locks the plug member and the counterpart relative to one another. A disadvantage of such a plug-in connector is that the plug member and counterpart must be matched relative to one another so that a plug member provided with the snap-on element cannot be connected to a counterpart that is not provided with an appropriate locking element.
DE 101 21 675 A1 discloses also that the snap-on element can be snapped into place on the outer thread of a counterpart. In order to ensure a sufficient tightness of the connection, the plug member must be inserted until it rests against a seal or gasket that is provided at the bottom of the counterpart. When doing so, the snap hook passes across the entire length of the thread. The snap hook is deflected when passing across the thread. The deflection of the snap hook is thus performed in a direction from the locking position into the release position. Accordingly, when inserting plug member and counterpart into one another, the user must additionally overcome the deflection force of the snap hook. A sufficient pressing action of plug member and counterpart for reaching a seal-tight connection can therefore not be ensured.